Glass cloth, prepreg, printed wiring boards, etc.

Abstract

The present disclosure relates to a glass cloth having glass yarns as warp and weft yarns, wherein the twist number of the weft yarn is 0.40 to 1.80 turns / 25 mm or -1.80 to 0.40 turns / 25 mm, and the absolute value difference in the twist numbers of the warp and weft yarns is 0.01 to 0.70 turns / 25 mm, and relates to a glass cloth wherein the amount of warp crimp of the weft yarn is 35 mm or less.

Description

Technical Field

[0001] The present invention relates to glass cloth, prepreg, printed wiring boards, and the like.

Background Art

[0002] Currently, the performance of information terminals such as smartphones is improving, and high-speed communication represented by 5G communication is progressing. Along with this, for printed wiring boards for high-speed communication, a lower dielectric constant and a lower dielectric tangent of the insulating material used for reducing transmission loss are required, and insulation reliability at a higher level than before is also required.

[0003] As insulating materials for printed wiring boards for high-speed communication, for example, prepregs and laminates using resin compositions containing polyphenylene ether with modified ends are known. Specifically, prepregs obtained by impregnating glass cloth with a low dielectric thermosetting resin (hereinafter collectively referred to as "matrix resin") containing polyphenylene ether with modified ends and drying them, and laminates obtained using the same are known (Patent Documents 1 and 2).

[0004] Here, Patent Document 3 describes that a quartz glass cloth is produced using 20 to 400 glass filaments made of quartz glass filaments having an average filament diameter of 3 to 20 μm and a standard deviation of the diameter of 0.15 or less. Regarding the quartz glass cloth, Patent Document 3 reports that more smoothness (smoothness of the surface of the glass cloth) can be obtained by reducing the number of twists of the glass filaments constituting the glass cloth or making it an untwisted yarn.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in Patent Document 3, there is room for improvement from the viewpoint of ensuring the appearance quality of the glass cloth. In particular, when manufacturing a glass cloth using glass yarns with a small number of twists or untwisted glass yarns as in Patent Document 3, the bundling of the glass yarns tends to deteriorate, so the amount of warp crimp of the weft of the glass cloth tends to be excessive. In this case, when the glass cloth is conveyed, the glass cloth is likely to meander, and as a result, wrinkles are likely to occur in the glass cloth, so there is a problem that it is difficult to ensure the appearance quality of the glass cloth.

[0007] Therefore, an object of the present invention is to provide a glass cloth having excellent smoothness and capable of ensuring excellent appearance quality even when using glass yarns (weft yarns) with a small number of twists. Another object of the present invention is to provide a prepreg obtained using the glass cloth, and also to provide a printed wiring board, an integrated circuit, and an electronic device obtained using the prepreg.

Means for Solving the Problems

[0008] One aspect of the present invention is as follows. [1] A glass cloth having glass yarns as warp and weft, wherein the number of twists of the weft is 0.40 to 1.80 turns / 25 mm or -1.80 to -0.40 turns / 25 mm, the absolute value difference between the number of twists of the warp and the weft is 0.01 to 0.70 turns / 25 mm, and the amount of warp crimp of the weft is 35 mm or less. [2] The glass cloth according to Item 1, wherein the silicon (Si) content in the glass yarn is 95.0 to 100% by mass in terms of silicon dioxide (SiO2). [3] The glass cloth according to item 1 or 2, wherein the silicon (Si) content in the glass fiber is 99.0 to 100% by mass in terms of silicon dioxide (SiO2). [4] The glass cloth according to any one of items 1 to 3, wherein the twist number of the warp is 0.40 to 1.80 turns / 25 mm or -1.80 to -0.40 turns / 25 mm. [5] The glass cloth according to any one of items 1 to 4, wherein the glass fiber is treated with a surface treatment agent containing a silane coupling agent. [6] The surface treatment agent is represented by the following formula (1): X(R) 3-n SiY n ···(1) (In the formula, X is an organic functional group having at least one of an amino group and an unsaturated double bond group having radical reactivity, Y is each independently an alkoxy group, n is an integer of 1 or more and 3 or less, and R is each independently a group selected from the group consisting of functional groups composed of hydrocarbon groups having 1 to 10 carbon atoms.) The glass cloth according to item 5, containing the silane coupling agent represented by the formula. [7] The glass cloth according to item 6, wherein X in the formula is an organic functional group that does not form a salt with an ionic compound. [8] The glass cloth according to item 6 or 7, wherein X in the formula does not contain an amine or an ammonium cation. [9] The glass cloth according to any one of items 6 to 8, wherein X in the formula is an organic functional group having at least one methacryloxy group and acryloxy group.

[10] The glass cloth according to any one of items 6 to 9, wherein R in the formula is a group selected from the group consisting of a methyl group, an ethyl group, and a phenyl group.

[11] The glass cloth according to any one of Items 1 to 10, wherein the TEX of the warp and weft is 0.5 to 40 g / 1000 m.

[12] The glass cloth according to any one of Items 1 to 11, wherein the bulk dielectric tangent of the glass constituting the glass yarn at 10 GHz is in the range of 0.001 or less.

[13] The glass cloth according to any one of Items 1 to 12, which is for a printed wiring board.

[14] A prepreg containing the glass cloth according to any one of Items 1 to 12, a thermosetting resin, and an inorganic filler.

[15] A printed wiring board including the prepreg according to Item 14.

[16] An integrated circuit including the printed wiring board according to Item 15.

[17] An electronic device including the printed wiring board according to Item 15. [Effect of the Invention]

[0009] An object of the present invention is to provide a glass cloth having excellent smoothness and ensuring excellent appearance quality even when using glass yarn with a small number of twists. Further, according to the present invention, it is possible to provide a prepreg obtained by using the glass cloth, and also to provide a printed wiring board, an integrated circuit, and an electronic device obtained by using the prepreg. [Embodiment for Carrying Out the Invention]

[0010] Hereinafter, this embodiment will be described. The present invention is not limited to only this embodiment, and can be variously modified and implemented within the scope of the gist thereof.

[0011] In this specification, the upper limit value or the lower limit value in the stepwise numerical range may be replaced by the upper limit value or the lower limit value in the corresponding other stepwise numerical range, and further, may be replaced by the corresponding value described in the examples. Also, in this specification, regarding the term "step", not only when it is an independent step, but also when it cannot be clearly distinguished from other steps, if the function of the step is achieved, it is included in this term. Furthermore, in this specification, various manufacturing, measurement, etc. are carried out based on the methods described in the examples unless otherwise specified.

[0012] [Embodiment 1] 〈Glass Cloth〉 This embodiment is a glass cloth having glass yarns as warp and weft, wherein the twist number of the weft is 0.40 to 1.80 turns / 25 mm or -1.80 to -0.40 turns / 25 mm, the absolute value difference between the twist numbers of the warp and the weft is 0.01 to 0.70 turns / 25 mm, and the warp crimp amount of the weft is 25 mm or less. According to this, even when using glass yarns with a small twist number, it is possible to provide a glass cloth having excellent smoothness and ensuring excellent appearance quality.

[0013] The glass cloth may be produced in a long shape having a longitudinal direction (in one aspect, the MD direction) and a transverse direction (in one aspect, the TD direction). In one aspect, the warp is held under tension on a loom, and the weft is woven so as to pass above and below the warp, thereby forming a plain weave structure glass cloth. According to this embodiment, for the weft yarn woven with respect to the warp yarn, glass yarn with a small number of twists is used. Using a weft yarn with a small number of twists is advantageous from the viewpoint of suppressing the unevenness in thickness (coefficient of variation in thickness) of the obtained glass cloth, that is, from the viewpoint of realizing a glass cloth with high smoothness. In this regard, the inventors of the present invention focused on actively ensuring the absolute value difference in the number of twists between the warp yarn and the weft yarn. This embodiment can control the amount of warp of the weft yarn within a small range by actively ensuring the absolute value difference in the number of twists between the warp yarn and the weft yarn while using glass yarn (weft yarn) with a small number of twists. In this case, the meandering of the glass cloth during the production or conveyance of the glass cloth can be suppressed.

[0014] In this embodiment, since the meandering of the glass cloth during the production or conveyance of the glass cloth can be suppressed, wrinkles are less likely to occur in the glass cloth, and as a result, it is easy to ensure the appearance quality. That is, according to this embodiment, a glass cloth with a small degree of deterioration in appearance quality with respect to various processes such as handling, storage, and transportation, in other words, a glass cloth with a small degree of deterioration in appearance quality over time is provided.

[0015] Such a glass cloth of this embodiment is suitable as a constituent element of a base material in a printed wiring board. By using the glass cloth of this embodiment, it is easy to realize a highly reliable printed wiring board.

[0016] Number of twists of glass yarn In this embodiment, the number of twists of the weft yarn is 0.40 to 1.80 turns / 25 mm or -1.80 to -0.40 turns / 25 mm. If the number of twists of the weft yarn is 0.40 turns / 25 mm or more or -0.40 turns / 25 mm or less, a sufficient number of twists of the weft yarn can be ensured, so that yarn breakage in the warping process can be suppressed, and the generation of fluff on the glass cloth can also be suppressed. If the number of twists of the weft yarn is 1.80 turns / 25 mm or less or -1.80 turns / 25 mm or more, the unevenness in thickness of the obtained glass cloth can be suppressed. In this case, the variation in dimensional changes in the warp and weft directions when a printed wiring board is manufactured can be suppressed. Moreover, according to the present embodiment, even when using such a weft yarn with a small number of twists, it is possible to provide a glass cloth having excellent smoothness and ensuring excellent appearance quality.

[0017] In the present embodiment, not only for the weft yarn, but also for the warp yarn, it is preferable that the number of twists is 0.40 to 1.80 turns / 25 mm or -1.80 to -0.40 turns / 25 mm. According to this, it is easier to achieve the effects of the present embodiment.

[0018] Note that the twist of the glass yarn is classified into the z-direction or the s-direction depending on the direction in which the twist is applied. In the present embodiment, the twist in the z-direction is defined as "positive" and the twist in the s-direction is defined as "negative". For example, in this specification, "a twist number of 1.00z" is expressed as having a twist number of 1.00, and "a twist number of 1.00s" is expressed as having a twist number of -1.00.

[0019] The twist number of the glass yarn can be adjusted, for example, in the process of twisting the glass yarn (twisting process). In one aspect, by converging the glass filaments, it is easier to increase the twist number of the glass yarn. Increasing the twist number of the glass yarn makes it easier to suppress the generation of flyers due to breakage of the glass filaments, and also makes it easier to suppress yarn breakage during the warping process of the glass cloth. On the other hand, due to the twist of the glass yarn, the width of the glass yarn is likely to be inhibited, and uneven thickness of the glass cloth is likely to occur at the twisted portion. Therefore, finding an appropriate twist number and using a glass yarn adjusted to such a twist number is advantageous for manufacturing a glass cloth with excellent quality.

[0020] The twist number of the weft yarn is preferably 0.40 to 1.50 turns / 25 mm or -1.50 to -0.40 turns / 25 mm, more preferably 0.50 to 1.30 turns / 25 mm or -1.30 to -0.50 turns / 25 mm, still more preferably in the range of 0.50 to 1.10 turns / 25 mm or -1.10 to -0.50 turns / 25 mm, even more preferably in the range of 0.60 to 1.00 turns / 25 mm or -1.00 to -0.60 turns / 25 mm, and particularly preferably in the range of 0.60 to 0.90 turns / 25 mm or -0.90 to -0.60 turns / 25 mm. The twist number of the warp is preferably 0.50 to 1.70 turns / 25 mm or -1.70 to -0.50 turns / 25 mm, more preferably 0.60 to 1.60 turns / 25 mm or -1.60 to -0.60 turns / 25 mm, still more preferably 0.60 to 1.40 turns / 25 mm or -1.40 to -0.60 turns / 25 mm, even more preferably 0.70 to 1.30 turns / 25 mm or -1.30 to -0.70 turns / 25 mm, and particularly preferably 0.80 to 1.10 turns / 25 mm or -1.10 to -0.80 turns / 25 mm. Also, from the viewpoint of excellent productivity of the glass cloth, it is preferable that the twist number of the weft is less than that of the warp.

[0021] Absolute value difference in twist number of warp and weft In this embodiment, the absolute value difference in the twist number of the warp and the weft is 0.01 to 0.70 turns / 25 mm. If the absolute value difference is 0.01 turns / m25 m or more, unevenness in the thickness of the glass cloth can be suppressed. In this case, the smoothness of the glass cloth can be enhanced, and the glass fibers are also easily separated during the production of the glass cloth. On the other hand, if the absolute value difference is 0.7 turns / 25 mm or less, it is easy to suppress the generation of fluff in the obtained glass cloth even when using a weft with a small twist number. From the same viewpoint, the absolute value difference in the twist number of the warp and the weft is preferably 0.05 turns / 25 mm or more, more preferably 0.08 turns / 25 mm or more, still more preferably 0.10 turns / 25 mm or more, even more preferably 0.13 turns / 25 mm or more, still more preferably 0.15 turns / 25 mm or more, more preferably 0.08 turns / 25 mm or more, still more preferably 0.20 turns / 25 mm or more, and most preferably 0.30 turns / 25 mm or more. Also, it is preferably 0.65 turns / 25 mm or less, more preferably 0.60 turns / 25 mm or less, still more preferably 0.0.55 turns / 25 mm, even more preferably 0.13 to 0.52 turns / 25 mm, still more preferably 0.50 turns / 25 mm or less, and particularly preferably 0.45 turns / 25 mm.

[0022] Constituting a glass cloth using weft yarns with a large number of twists is one of the useful means for suppressing the generation of hairiness in the glass cloth. However, in this case, the excellent smoothness of the glass cloth cannot be achieved. Here, the inventors of the present invention focus on actively ensuring the absolute value difference in the number of twists of the warp yarns and weft yarns of the glass cloth. The greater the absolute value difference in the number of twists of the warp yarns and weft yarns of the glass cloth, the greater the amount of warp bending of the weft yarns may be. When the amount of warp bending of the weft yarns increases, in the process of processing a prepreg using the obtained glass cloth, the glass cloth is likely to snake during conveyance, and as a result, the yield of the prepreg is likely to decrease. On the other hand, the inventors have found that in the warp warping process, taper control of the yarn tension is performed, that is, the yarn tension is increased as it approaches both ends based on the yarn tension at the central part of the yarn.

[0023] In the present embodiment, by performing the taper control of the yarn tension in a preferable manner, even if the absolute value difference in the number of twists of the warp yarns and weft yarns is increased, the amount of warp bending of the weft yarns can be easily reduced. In this case, it is easy to achieve both suppression of hairiness generation and reduction of thickness unevenness in the glass cloth, and it is also easy to achieve suppression of the snaking of the glass cloth during conveyance of the glass cloth, improvement of the yield of the prepreg.

[0024] The absolute value difference in the number of twists of the warp yarns and weft yarns is derived, for example, by calculating the difference between the absolute value of the number of twists of the warp yarns and the absolute value of the number of twists of the weft yarns, and obtaining the absolute value of the difference.

[0025] Amount of warp bending of the weft yarn In the present embodiment, the amount of warp bending of the weft yarns is 35 mm or less. If the amount of warp bending of the weft yarns is 35 mm or less, the snaking of the glass cloth can be prevented during conveyance of the glass cloth. In this case, wrinkles are less likely to occur in the glass cloth and, consequently, in the obtained prepreg. From the same viewpoint, the amount of warp bending of the weft yarns is preferably 30 mm or less, more preferably 25 mm or less, still more preferably 20 mm or less, even more preferably 18 mm or less, particularly preferably 16 mm or less, and most preferably 14 mm or less. The amount of warp bending of the weft yarns may be 0 mm or more.

[0026] As described above, by performing the taper control of the yarn tension in a preferable manner, even if the absolute value difference in the number of twists of the warp and weft yarns is increased, it is easy to reduce the amount of warp of the weft yarn. That is, it is possible to appropriately control the amount of warp of the weft yarn according to the number of twists of the warp and weft yarns and the conditions of the taper control of the yarn tension.

[0027] Average filament diameter of glass yarn The average filament diameter of the glass filament is preferably 2.5 to 9.0 μm, more preferably 2.5 to 7.5 μm, still more preferably 3.5 to 7.0 μm, even more preferably 3.5 to 6.0 μm, and particularly preferably 3.5 to 5.0 μm.

[0028] TEX of glass yarn The TEX of the glass yarn is preferably 0.5 to 40 g / 1000 m, more preferably 0.8 to 35 g / 1000 m, still more preferably 1.0 to 30 g / 1000 m, even more preferably 1.5 to 25 g / 1000 m, and particularly preferably 2.0 to 20 g / 1000 m. If the TEX is 0.5 g / 1000 m or more, it is easy to prevent the glass yarn from breaking in the manufacturing process of the glass cloth, and it is also easy to prevent the cutting of the glass cloth. If the TEX is 40 g / 1000 m or less, it is easy to avoid the situation where the thickness of the glass cloth becomes too thick, and it is easy to obtain the effect (for example, the effect of reducing the thickness unevenness of the glass cloth) by ensuring the absolute value difference in the number of twists of the warp and weft yarns.

[0029] Weave density The weave density of the warp and weft yarns is preferably 10 to 120 threads / 25 mm, more preferably 40 to 100 threads / 25 mm, and still more preferably 40 to 100 threads / 25 mm.

[0030] Thickness of glass cloth The thickness of the glass cloth is preferably 5 to 150 μm, more preferably 10 to 120 μm, still more preferably 15 to 100 μm, even more preferably 20 to 90 μm, and particularly preferably 30 to 70 μm. When the thickness of the glass cloth is within the above range, it becomes easier to obtain the effect (for example, the effect of reducing the thickness unevenness of the glass cloth) by ensuring the absolute value difference in the number of twists of the warp and weft yarns.

[0031] Coefficient of variation of the thickness of the glass cloth The coefficient of variation of the thickness of the glass cloth is preferably 10% or less, more preferably 8% or less, still more preferably 6% or less, even more preferably 5% or less, and particularly preferably 3% or less. In one aspect, "glass cloth having excellent smoothness" means "the glass cloth having a coefficient of variation of the thickness of the glass cloth of 10% or less". By using the glass cloth having a coefficient of variation of the thickness of the glass cloth within the above range, it is easy to realize a prepreg excellent in dimensional stability, and thus a printed wiring board excellent in dimensional stability. Weave structure Examples of the weave structure of the glass cloth include plain weave, matt weave, twill weave, and satin weave. Among them, the plain weave structure is preferable as the weave structure of the glass cloth.

[0032] Glass type Examples of the glass type constituting the glass yarn include glass called E-glass (alkali-free glass). Also, examples of the glass type constituting the glass yarn include L-glass, NE-glass, D-glass, L2-glass, T-glass, silica glass, and quartz glass. From the viewpoint of realizing excellent dielectric properties, examples of the glass type constituting the glass yarn preferably include L-glass, L2-glass, silica glass, and quartz glass, and among them, silica glass and quartz glass are more preferably included. Also, from the viewpoint of enhancing the dimensional stability of the obtained prepreg, examples of the glass type constituting the glass yarn preferably include S-glass, T-glass, silica glass, and quartz glass, and among them, silica glass and quartz glass are more preferably included as the glass type constituting the glass yarn.

[0033] In a glass cloth (silica glass cloth) composed of silica glass and a glass cloth (quartz glass cloth) composed of quartz glass, the Si content of the glass fiber is preferably 95.0 to 100% by mass in terms of SiO2, more preferably in the range of 99.0 to 100% by mass, still more preferably 99.5 to 100% by mass, even more preferably 99.7 to 100% by mass, and particularly preferably 99.9 to 100% by mass. Since the glass fiber with an Si content of 95.0% by mass or more has high hardness of the glass itself, it is likely to cause uneven thickness of the glass cloth at the twisted portion of the glass fiber. Therefore, when using glass with an Si content of 95.0% by mass or more, it is likely to benefit from the effect (for example, the effect of reducing uneven thickness of the glass cloth) by ensuring the absolute value difference in the twist numbers of the warp and weft yarns.

[0034] Bulk dielectric tangent of glass In the glass cloth of the present embodiment, the bulk dielectric tangent at 10 GHz for the glass raw material constituting the glass cloth is measured by a method using a split cylinder resonator (a method using a resonance method), specifically, the method described in the examples. Here, as the glass raw material, for example, glass fiber, glass filament, and glass type, etc. may be used.

[0035] The bulk dielectric tangent at 10 GHz is preferably 0.001 or less, more preferably 0.0008 or less, still more preferably 0.0006 or less, even more preferably 0.0004 or less, and particularly preferably 0.0003 or less. According to this, it is easier to exhibit the effects of the present disclosure.

[0036] Silane coupling agent The glass fiber (including glass filament) constituting the glass cloth is preferably surface-treated with a silane coupling agent. In one aspect, the surface treatment agent for the glass fiber contains a silane coupling agent. Examples of the silane coupling agent include the following formula (1): X(R) 3-n SiY n ···(1) {In the formula, X is an organic functional group having at least one of an unsaturated double bond group having radical reactivity such as a carbon-carbon double bond having radical reactivity and an amino group, Y is each independently an alkoxy group, n is an integer of 1 to 3, and R is a group selected from the group consisting of hydrocarbon groups having 1 to 10 carbon atoms.} The silane coupling agent represented by is preferred. In the above formula (1), R is preferably a group selected from the group consisting of a methyl group, an ethyl group, and a phenyl group.

[0037] In the present embodiment, from the viewpoint of easily obtaining a glass cloth having excellent dielectric properties, X in the formula (1) is preferably an organic functional group that does not form a salt with an ionic compound. Further, from the viewpoint of excellent reactivity with the matrix resin, X in the formula (1) is more preferably an organic functional group having one or more methacryloxy groups or acryloxy groups. Note that, from the viewpoint of good reactivity with a radical-reactive matrix resin, X in the formula (1) is preferably an amine such as a primary amine, a secondary amine, and a tertiary amine, and preferably does not contain an ammonium cation such as a quaternary ammonium cation.

[0038] Regarding Y in the above formula (1), as the alkoxy group, an alkoxy group having 1 to 5 carbon atoms (the number of carbon atoms is 1, 2, 3, 4, or 5) is preferred from the viewpoint of easily achieving stabilization treatment on the glass cloth.

[0039] As the surface treatment agent, the silane coupling agent represented by the formula (1) may be used alone, or may be used as a mixture of two or more silane coupling agents having different Xs in the formula (1). Examples of the silane coupling agent represented by the formula (1) include monomers such as vinyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, and 5-hexenyltrimethoxysilane, and mixtures in which these monomers are used in combination.

[0040] The molecular weight of the silane coupling agent is preferably from 100 to 600, more preferably from 150 to 500, still more preferably from 200 to 450. Among these, it is particularly preferable to use two or more silane coupling agents having different molecular weights. By treating the surface of the glass fiber with two or more silane coupling agents having different molecular weights, the density of the treatment agent on the glass surface tends to be high, and in this case, the reactivity with the matrix resin tends to be further improved.

[0041] From the viewpoint of being difficult to inhibit the reactivity with the resin, the silane coupling agent is preferably nonionic. Among nonionic silane coupling agents, a silane coupling agent having at least one group selected from the group consisting of a vinyl group, a methacryloxy group, and an acryloxy group is preferable, and among these, a silane coupling agent having at least one methacryloxy group or acryloxy group is particularly preferable. By not inhibiting the reactivity with the resin, the heat resistance and reliability of the printed wiring board can be enhanced.

[0042] In one aspect, in formula (1), X is an organic functional group having at least one of the above unsaturated double bond group and amino group. Therefore, not only the aspect where X has both the above unsaturated double bond group and the above amino group, but also the aspect where X has the above unsaturated double bond group but does not have the above amino group and the aspect where X does not have the above unsaturated double bond group but has the above amino group are both included in the scope of formula (1). However, X in formula (1) is preferably the above unsaturated double bond group and preferably does not contain an amino group.

[0043] <Method for manufacturing glass cloth> One aspect of the present embodiment is a manufacturing method for manufacturing the above glass cloth. Such a manufacturing method includes, for example, the following steps: A step of warping the warp yarns to obtain a sectional beam of the warp yarns (warping step), A step of weaving a glass cloth using the sectional beam (weaving step), and has The warping process performs taper control to increase the yarn tension as approaching both ends based on the yarn tension at the central part of the yarn. It is a method for manufacturing a glass cloth.

[0044] After the warping process, the method for manufacturing a glass cloth may include a process of combining the obtained section beams to produce one room beam (beaming process). Thereby, a glass cloth can be woven using the room beam obtained in the beaming process, and in this case, it is easy to manufacture a glass cloth excellent in various characteristics.

[0045] In addition, the method for manufacturing a glass cloth may include a process of heating and degreasing the woven glass cloth (heating and degreasing process). Thereby, it is easy to suitably reduce the dielectric loss tangent of the glass cloth.

[0046] In addition, the method for manufacturing a glass cloth may include a process of applying a treatment liquid containing a silane coupling agent to the glass cloth (coating process), and a process of drying the treatment liquid and fixing the silane coupling agent on the surface of the glass filament (drying process). Thereby, it is easy to suitably perform surface treatment on the glass cloth.

[0047] In addition, the method for manufacturing a glass cloth may include a process of washing a silane coupling agent (in one aspect, a silane coupling agent that did not form a chemical bond with the surface of the glass filament) and performing a fiber opening treatment on the glass yarn (fiber opening process). Thereby, it is easy to suitably perform fiber opening on the glass cloth.

[0048] The coating process, drying process, and fibrillation process may be performed on the glass yarn either before or after the weaving process of weaving the glass yarn to obtain a glass cloth. The order of the heating and degreasing process, coating process, drying process, and fibrillation process can be appropriately interchanged and repeated. When the washing process is performed after the weaving process, a high-pressure water spray or the like may be used in the washing process to also serve as the fibrillation process. Note that the composition of the glass cloth usually does not change before and after fibrillation.

[0049] Sizing process In the sizing process, the warp yarns are sized to obtain a warp beam. The sizing process is, for example, a process of aligning a plurality of warp yarns so as to have a desired weaving density and width, and a process of performing sizing treatment on the warp yarns, and may have. Among these, in the sizing treatment, in order to suppress the generation of fluff in the glass yarn and to prevent water absorption, a sizing agent mainly composed of starch and / or polyvinyl alcohol (PVA) can be adhered to the surface of the glass yarn.

[0050] Here, in the sizing process, taper control is performed in which the yarn tension is increased as approaching both ends with reference to the yarn tension at the central part of the yarn. Even when using a glass yarn with a small number of twists as the weft yarn, it is advantageous to perform such taper control in order to suppress the amount of warp of the weft yarn. In taper control, for example, when sizing 800 warp yarns, the yarn tensions of the 400th and 401st yarns at the central part are set to 5 g, and the yarn tensions of the 1st and 800th yarns at both ends are set to 8 g. Then, for the yarn tensions of the 2nd to 399th and 402nd to 799th yarns, the respective yarn tensions are controlled so that the yarn tension continuously increases as approaching both ends. The yarn tension (taper control amount) that increases as approaching both ends is the following formula: Taper control amount: (8 g - 5 g) ÷ 399 yarns ≒ 0.0075 g / yarn It is calculated according to this. In the examples in this specification, the 341st and 460th yarn tensions are 5 g + 0.0075 g × 59 ≒ 5.4 g. Here, for the sake of convenience of explanation, the second decimal place is rounded off.

[0051] The warp thread selected as the central part is 1 when the total number of warp threads is odd, and 2 when the total number of warp threads is even. As in the above example, when the total number of warp threads is even, the same yarn tension is set for the two warp threads selected as the central part.

[0052] Beaming process In the beaming process, the sectional beams obtained in the above warping process are combined to produce one room beam (warp beam). According to the beaming process, it is easy to produce a room beam in a state that can be set on a loom based on the sectional beams obtained in the warping process. The number of warp threads in the room beam and the number of bundles of sectional beams to be beamed are appropriately adjusted according to the warp weaving density and width of the glass cloth. In one aspect, the number of warp threads in the sectional beam is about 800, and the number of bundles of sectional beams to be beamed is about 4.

[0053] In one aspect, when four sectional beams obtained in the warping process are combined to produce one room beam, the warp threads are sequentially provided from each sectional beam. For example, when using four bundles of sectional beams (A) to (D) and the first warp thread of room beam (A) is referred to as "(A)-1", (A)-1, (B)-1, (C)-1, (D)-1, (A)-2, (B)-2, (C)-2, (D)-2, (A)-3 ···, the warp threads are sequentially provided from each sectional beam. According to this, it is easy to obtain the effect of taper control performed in the warping process. That is, it is easy to preferably control the yarn tension at both ends of the glass cloth higher than that at the central part. In this case, even when using a weft yarn with a small number of twists, it is easy to control the amount of warp crimp of the weft yarn to be small.

[0054] Weaving process In the weaving process, a glass cloth is woven using a beam, preferably a loom beam produced in the beaming process. Here, glass yarns with different twist numbers are used as the warp yarns and the weft yarns, respectively, in order to ensure an absolute value difference in the twist numbers of the warp yarns and the weft yarns. From the viewpoint of excellent productivity of the glass cloth, it is preferable that the twist number of the weft yarns is less than that of the warp yarns.

[0055] Heating and degreasing process In the heating and degreasing process, the woven glass cloth is heated and degreased. When sizing treatment is performed on the warp yarns in the warping process, the sizing agent attached to the warp yarns is preferably removed in this heating and degreasing process. However, the heating and degreasing process may be performed regardless of whether sizing treatment is performed.

[0056] As means for heating and degreasing, known heating methods, heating media, heating mechanisms, heating devices, and heating parts can be used. Specifically, as heating and degreasing, a method of heating and degreasing the glass cloth at a temperature of 600 to 1600°C; a method of heating under the condition that the maximum heating temperature is 100 to 600°C in a vacuum or a gas with a dew point of 15°C or lower, and the heating amount represented by the heating temperature (°C) × heating time (h) of 100°C or higher is 450 (°C·h) or more; etc. are exemplified.

[0057] When performing the heating and degreasing treatment in a closed system, from the viewpoint of preferably performing heating by a heating means, it is preferable to place the glass cloth in a heating furnace, and from the viewpoint of space saving of the storage space, it is preferable to heat while storing the glass cloth in a rolled state. Further, from the viewpoint of increasing the removal efficiency of organic substances and shortening the removal time of organic substances, it is also preferable to heat while conveying the glass cloth in the heating furnace.

[0058] When performing the heating and degreasing treatment in a closed system, from the viewpoint of ensuring the heated area, it is preferable to heat while conveying the glass cloth. The conveyance of the glass cloth can be performed, for example, by combining a mechanism for unwinding the rolled glass cloth (unwinding mechanism) and a mechanism for winding up the unwound glass cloth (winding-up mechanism).

[0059] The heat degreasing process preferably includes a step of heat-treating the glass cloth in the range of 600 to 1600 °C (heat treatment step). In the heat treatment step, by heat degreasing a raw glass cloth having a softening point of the glass fiber of 900 °C or higher in the temperature range of 600 to 1600 °C, it is possible to lower the dielectric tangent of the glass cloth while suppressing damage to the glass cloth. When the heat degreasing temperature is 600 °C or higher, it is easy to effectively lower the dielectric tangent of the obtained glass cloth. When the heat degreasing temperature is 1600 °C or lower, it is easy to suppress the devitrification phenomenon of the glass, and thus it is easy to prevent a decrease in the strength of the glass cloth. From the same viewpoint, the heat degreasing temperature is more preferably 700 to 1500 °C, still more preferably 800 to 1400 °C, even more preferably 900 to 1300 °C, and particularly preferably 1000 to 1200 °C.

[0060] In the heat degreasing process, the heating time is preferably 10 minutes or less, more preferably 5 minutes or less, still more preferably 2 minutes or less, and particularly preferably 90 seconds or less. When the heating time is 10 minutes or less, the damage to the glass cloth is reduced, so it is easy to avoid situations such as partial holes opening in the glass cloth during processing and the glass cloth being cut. The heating time may be, for example, 1 second or more, 5 seconds or more, 10 seconds or more, or 15 seconds or more.

[0061] (Heating furnace) As the heating furnace, which is the heating means in the heat degreasing process, any one can be used as long as the above conditions in heat degreasing can be achieved. For example, an electric heater, a burner, etc. can be mentioned. Also, a plurality of heating furnaces may be combined. As the heating furnace, a gas single radiant tube burner or an electric heater is preferably used.

[0062] From the perspective of efficiently removing the organic substances adhering to the glass cloth surface, a continuous method that can heat the glass cloth while continuously passing it through a heating furnace is preferred over a batch method in which the glass fiber fabric is wound around a core and the glass cloth is heated at a predetermined ambient temperature. Furthermore, a method that can continuously wash the glass cloth with washing water having a low metal ion content, such as reverse osmosis (RO) water or ion-exchanged water, is also preferred.

[0063] (Contact member for heating the glass cloth) As a method for heating the glass cloth, the above heating furnace may be used, but from the perspective of easily realizing low running costs, the glass cloth may be heated by bringing a member (contact member) heated to a predetermined temperature into contact with the glass cloth.

[0064] As the contact member, a roll is preferred from the perspective of easily transporting the glass cloth. As this type of roll, a roll heated by an induction heating method that can be used in a high-temperature region and has relatively little variation in temperature in the width direction is preferred. When heating the glass cloth with the contact member, it is expected that the temperature of the contact member and the surface temperature of the glass cloth will be approximately equal.

[0065] In order to remove foreign substances (for example, carbides) adhering to the roll during continuous heating of the glass cloth, it is preferable to adopt a method equipped with a mechanism for removing the foreign substances, such as a blade or the like.

[0066] (Means for applying high-temperature steam to the glass cloth) As a method of heating a glass cloth, high-temperature steam may be applied to the glass cloth. The steam applied to the glass cloth may contain, for example, a volatile solvent, water vapor, etc., and may also contain a gas other than water vapor. Among them, as the steam applied to the glass cloth, water vapor is preferable from the viewpoint of suppressing toxicity to the human body and from the viewpoint that the decomposition of the sizing agent used for glass fibers is likely to be promoted. The temperature of the high-temperature steam may be a method in which high-temperature steam and heated air are supplied at an arbitrary ratio if necessary, in order to make the surface temperature of the glass cloth higher than 650°C. The temperature of the high-temperature steam is 400°C or higher, preferably 450°C or higher, more preferably 550°C or higher, still more preferably 600°C or higher, and particularly preferably 650°C or higher. As means for applying the steam, spraying, shower diffusion, jet nozzles, etc. may be used. The gas discharged from the heating furnace may be reused as high-temperature steam.

[0067] When the amount of sodium ions adhering to the surface of the glass cloth exceeds a predetermined amount, if the glass cloth is heated and degreased at 700°C or higher, the tensile strength of the glass cloth is likely to be significantly reduced due to the devitrification phenomenon of the fused silica glass. In order to suppress the devitrification phenomenon, it is advisable to wash the glass cloth with water having a sodium ion content of 20 ppm or less before heating and degreasing. Thereby, it is easy to reduce the amount of sodium ions in the glass surface. In this case, even if heating and degreasing are performed at 700°C or higher, it is easy to suppress the devitrification phenomenon of the fused silica glass. By maintaining the strength of the glass cloth after heating and degreasing, it is easy to suppress wrinkles and / or scratches, etc. in the process of treating the glass cloth with a surface treatment agent.

[0068] From the viewpoint of preferably obtaining the effects of this embodiment, the sodium ion content in the water used for washing is preferably 18 ppm or less, more preferably 15 ppm or less, still more preferably 12 ppm or less, even more preferably 10 ppm or less, and particularly preferably 7 ppm or less. When the sodium ion content exceeds 20 ppm, it is difficult to suppress the devitrification phenomenon of the fused silica glass when heating and degreasing at 700°C or higher. In this case, a decrease in the tensile strength of the glass cloth is likely to occur. The sodium ion content may be 0 ppm, or may exceed 0 ppm.

[0069] As means for cleaning the glass cloth, for example, a method using ultrasonic waves (specifically, a method using an ultrasonic vibrator, etc.), a method using a spray (specifically, a method using a high-pressure spray, etc.), a method of spraying steam, etc. can be mentioned. From the viewpoint of being easy to perform cleaning at low cost, it is preferable to immerse the glass cloth in a water tank storing cleaning water (water with a sodium ion content of 20 ppm or less), then remove the excess cleaning water with a squeeze roller or the like, and then dry the glass cloth. In this case, the immersion time may be, for example, 2 seconds or more, 5 seconds or more, 10 seconds or more, and 15 seconds or more, and may also be 120 seconds or less, 90 seconds or less, 60 seconds or less, and 45 seconds or less.

[0070] Water with a sodium ion content of 20 ppm or less may be produced, for example, by filtration using an RO membrane, deionization using an ion exchange resin, etc. "Water with a sodium ion content of 20 ppm or less" may contain other liquid components (liquids other than water) within a range that does not inhibit the effects of this embodiment.

[0071] Coating process The coating process is a process of applying a treatment liquid containing a silane coupling agent to the glass cloth. As a method of applying the treatment liquid to the glass cloth, for example, (a) A method of immersing and / or passing the glass cloth through the treatment liquid stored in a bath (hereinafter referred to as the "immersion method"). (i) A method of directly applying the treatment liquid to the glass cloth using a roll coater, a die coater, a gravure coater, etc. etc. can be mentioned. When the immersion method is adopted, the immersion time of the glass cloth in the treatment liquid is preferably set to 0.5 seconds or more and 1 minute or less. The treatment liquid in the coating process has, for example, a silane coupling agent concentration of 0.01 to 1.5 wt%.

[0072] Drying process In the drying process, the treatment liquid is dried and the silane coupling agent is fixed on the surface of the glass filament. Examples of the drying method, preferably heat drying, include hot air, electromagnetic waves, and the like.

[0073] The drying temperature is preferably 80°C or higher, more preferably 90°C or higher, so that the reaction between the silane coupling agent and the glass can proceed sufficiently. From the viewpoint of preventing the deterioration of the organic functional groups of the silane coupling agent, the drying temperature is preferably 300°C or lower, more preferably 180°C or lower.

[0074] Fibrillation process In the fibrillation process, the silane coupling agent (in one aspect, the silane coupling agent that did not form a chemical bond with the surface of the glass filament) is washed, and the fibrillation treatment of the glass yarn is performed. Examples of the fibrillation method include, for example, a method of fibrillating a glass cloth with spray water (high-pressure water fibrillation), a vibro washer, ultrasonic water, a mangle, and the like. During the fibrillation process, by reducing the tension applied to the glass cloth, it is easier to widen the width of the glass yarn, and it is also easier to remove to some extent the silane coupling agent that did not chemically bond to the glass surface. In order to suppress the decrease in the tensile strength of the glass cloth due to the fibrillation process, it is preferable to take measures such as reducing the friction of the contact members when weaving the glass yarn and increasing the adhesion amount of the sizing agent.

[0075] 〈Prepreg〉 A further aspect of this embodiment is a prepreg. Such a prepreg contains at least the above-mentioned glass cloth and the matrix resin impregnated in the glass cloth.

[0076] As the matrix resin, either a thermosetting resin or a thermoplastic resin can be used.

[0077] Examples of the thermosetting resin include, for example, a) A compound having an epoxy group and a compound having at least one of an amino group, a phenol group, an acid anhydride group, a hydrazide group, an isocyanate group, a cyanate group, and a hydroxyl group that reacts with the epoxy group are reacted and cured without a catalyst or by adding a catalyst having a reaction catalytic ability such as an imidazole compound, a tertiary amine compound, a urea compound, or a phosphorus compound to form an epoxy resin; b) A radical polymerization type curable resin formed by curing a compound having at least one of an allyl group, a methacryl group, and an acryl group using a thermal decomposition type catalyst or a photodecomposition type catalyst as a reaction initiator; c) A maleimide triazine resin formed by reacting and curing a compound having a cyanate group and a compound having a maleimide group; d) A thermosetting polyimide resin formed by reacting and curing a maleimide compound and an amine compound; e) A benzoxazine resin formed by crosslinking and curing a compound having a benzoxazine ring by heat polymerization; etc. can be mentioned.

[0078] Examples of the thermoplastic resin include, for example, polyphenylene ether, modified polyphenylene ether, polyphenylene sulfide, polysulfone, polyethersulfone, polyarylate, aromatic polyamide, polyetheretherketone, thermoplastic polyimide, insoluble polyimide, polyamideimide, and fluororesin, etc. are exemplified.

[0079] In this embodiment, a thermosetting resin and a thermoplastic resin may be used in combination. The prepreg may contain an inorganic filler if desired. The inorganic filler is preferably used in combination with the thermosetting resin. Examples of the inorganic filler include aluminum hydroxide, zirconium oxide, calcium carbonate, alumina, mica, aluminum carbonate, magnesium silicate, aluminum silicate, silica, talc, short glass fibers, aluminum borate, and silicon carbide.

[0080] 〈Printed Wiring Board〉 A further aspect of the present embodiment is a printed wiring board. Such a printed wiring board contains the above prepreg. Thereby, a printed wiring board excellent in insulation reliability can be provided. 〈Integrated Circuit, and Electronic Device〉 A further aspect of the present embodiment is an integrated circuit, and an electronic device. Such an integrated circuit, and an electronic device contain the above printed wiring board. Thereby, an integrated circuit, and an electronic device excellent in various characteristics can be provided.

Examples

[0081] Examples and comparative examples are given to further explain the present embodiment. The present embodiment is not limited to only the examples. The values of various parameters described in this specification were measured by the methods described in the examples column.

[0082] [Measurement, and Evaluation] 〈Thickness of Glass Cloth, and Standard Deviation of the Thickness〉 In accordance with 7.10 of JIS R 3420, using a micrometer, while gently rotating the spindle, it was lightly contacted parallel to the measurement surface, and the scale value when the ratchet made three clicks was read. The read value was treated as the thickness of the glass cloth. JIS R 3420 stipulates general test methods for products such as glass long fibers and glass cloth using glass long fibers.

[0083] The thickness of the glass cloth was measured 50 times while changing the measurement position, and from the average value and standard deviation, the following formula: Coefficient of variation (%) = {(standard deviation of thickness) / (average value of thickness)} × 100 was used to obtain the coefficient of variation (%) of the thickness of the glass cloth.

[0084] 〈Amount of Warp of Weft〉 Measurement was carried out in accordance with JIS L1096, and the amount of warp of the weft (mm) was obtained. Specifically, the following operations (1) to (3): (1) One warp yarn in the glass cloth stretched over a pair of rolls was visually observed. (2) Using the TD tangent line of the roll and the cloth as a reference line, the displacement amount from the reference line was measured. (3) The difference between the maximum and minimum values of the measured displacement amount was calculated, and this operation was performed 5 times to calculate the average value of the difference. Based on this, the obtained average value was treated as the "warp yarn bending amount".

[0085] 〈TEX of glass yarn〉 Measurement was carried out in accordance with JIS R3911, and the TEX (g / 1000m) of the glass yarn was obtained. Note that the values described as "TEX" in the following table are the values measured for the glass yarn which is the raw material of the glass cloth. However, this value is also treated as the value measured for the glass yarns (warp and weft) extracted from the glass cloth obtained using the glass yarn and then measured for these.

[0086] 〈Twist number of glass yarn and absolute value difference thereof〉 Measurement was carried out in accordance with JIS R3420, and the twist number (turns / 25 mm) of the glass yarn was obtained. When measuring the twist number, in order to accurately measure the twist number of the glass yarn in the glass cloth, the glass yarn was pulled out from the glass cloth and the measurement was carried out for the glass yarn. Regarding the obtained values, the twist in the z direction was treated as positive and the twist in the s direction was treated as negative. For example, a twist of 1.00z (a twist of 1.00 (turns / 25 mm) in the z direction) was treated as +1.00, and a twist of 1.00s (a twist of 1.00 (turns / 25 mm) in the s direction) was treated as -1.00. Then, the following formula: Absolute value difference of twist number = |Twist number of warp yarn - Twist number of weft yarn| was used to calculate the absolute value difference (turns / 25 mm) of the twist numbers of the warp and weft yarns.

[0087] 〈Dielectric loss tangent of glass〉 A glass plate with a thickness of 300 μm having the same type and the same composition as the glass cloth was prepared. Then, using the thickness obtained from the thickness measurement of the glass plate, the bulk dielectric tangent of the glass at 10 GHz was measured. Specifically, in accordance with IEC 62562, the glass plate sampled to the size required for measurement with a split cylinder resonator was conditioned by storing it in a thermo-hygrostat oven at 23 °C and 50% RH for 8 hours. Thereafter, using a split cylinder resonator (manufactured by EM Lab) and an impedance analyzer (manufactured by Agilent Technologies), the dielectric properties at 10 GHz were measured. The measurement was performed 5 times for each sample, and the average value was obtained. Note that IEC 62562 stipulates a method for measuring the dielectric properties of fine ceramics materials for dielectric substrates mainly used in microwave circuits in the microwave band.

[0088] <Fuzz Quality> The glass cloths obtained in the examples and comparative examples were visually inspected using a roll-to-roll inspection table while applying a tension of 100 N / 1000 mm and irradiating with a halogen lamp to determine the number of fuzzes, particularly the number of fuzzes with protrusions of 1 mm or more. The number of fuzzes per 1 m 2 was treated as the fuzz frequency, and the fuzz quality was evaluated according to the following criteria using this value. (Measurement Criteria) Fuzz Quality A: The fuzz frequency is 15 pieces / m 2 or less. Fuzz Quality B: The fuzz frequency is 16 to 30 pieces / m 2 is. Fuzz Quality C: The fuzz frequency is 31 pieces / m 2 or more.

[0089] Looking at the relationship between the "twist number of the weft yarn" and the "hairiness quality" in the following table, good hairiness quality was observed in the examples where the twist number of the weft yarn was relatively large, while a hairiness quality C evaluation was confirmed in Comparative Example 3 with the least twist number of the weft yarn. Regarding the "twist number of the weft yarn" and the "hairiness quality", it is inferred that the lower the twist number of the weft yarn in the glass cloth, the worse the hairiness quality. According to the glass cloth of the example where good hairiness quality was observed, an improvement in the reliability of the printed wiring board obtained using this (for example, suppression of insulation failure) is expected.

[0090] [Examples and Comparative Examples] 〈Example 1〉 Glass yarn with a SiO2 composition amount exceeding 99.9% by mass (bulk dielectric tangent of glass @10 GHz = 0.0002) was used as the warp yarn and the weft yarn. In the warp beam warping process, 857 glass yarns (filament diameter = 5.0 μm, number of filaments = 100) having a twist number of 5.0 TEX and +1.00 were arranged side by side, and section beam processing was performed. The tension during warp beam warping was set to 8.0 g / strand at the 1st and 857th strands, and 5.0 g / strand at the 429th strand. For the 2nd to 428th strands and the 430th to 856th strands, taper control was performed such that the yarn tension was increased by 0.007 g for each strand approaching both ends based on the yarn at the 429th strand (the yarn located in the center of the 857 strands). The yarn tension was controlled with the value rounded to the second decimal place. A total of 4 section beams were produced under the above conditions.

[0091] The obtained section beams were handled so as to be arranged in order, and a loom beam with a total of 3428 warp yarns was produced. Using the obtained loom beam, a glass cloth having a weaving density of 65.0 warp yarns / 25 mm and 66.9 weft yarns / 25 mm and a width of 1310 mm was woven on an air jet loom. At this time, 5.0 TEX glass yarn was used as the weft yarn, and the twist number of the glass yarn and the weaving conditions were adjusted so that the twist number of the weft yarn of the glass cloth was +0.65. The raw cloth of the obtained glass cloth was washed with ion-exchanged water, then dried, and heat degreasing treatment was performed at 800 °C for 50 seconds.

[0092] Subsequently, the glass cloth after the heat degreasing treatment was immersed in the treatment liquid. The treatment liquid was prepared by dispersing 0.2% of 3-methacryloxypropyltrimethoxysilane; Z6030 (manufactured by Dow Corning Toray Co., Ltd.), which is a silane coupling agent, in pure water adjusted to pH = 3 with acetic acid. The glass cloth wrung out of the treatment liquid was dried by heating at 110°C for 1 minute. The dried glass cloth was subjected to fibrillating treatment by irradiating ultrasonic waves with a frequency of 25 kHz and an output of 0.50 W / cm 2 in water, and then dried at 110°C for 1 minute. Thus, a glass cloth subjected to surface treatment was obtained.

[0093] In the following table, in the warp beam forming process, the yarn tension (g / yarn) at the central part (the 429th yarn located at the center of 857 yarns) is denoted as "center"; the respective yarn tensions (g / yarn) at both ends (the 1st and 857th yarns located at both ends of 857 yarns) are denoted as "both ends"; in the taper control of increasing the yarn tension as approaching from the central part to both ends, the increase amount of the yarn tension (g / yarn) is denoted as "taper amount"; are shown.

[0094] 〈Examples 2, 3, 4, 9, 10〉 Glass cloths were obtained in the same manner as in Example 1, except that each value and each control were changed as described in the table.

[0095] 〈Example 5〉 Glass yarn with a SiO2 composition content exceeding 99.9% by mass (bulk dielectric tangent of glass @10 GHz = 0.0002) was used as the warp and weft yarns. In the warp warping process, 689 glass yarns (filament diameter = 5.0 μm, number of filaments = 200) having a count of 9.8 TEX and a twist number of +1.00 were arranged side by side, and section beam processing was performed. The tension during warp warping was set to 8.0 g / strand at the 1st and 689th strands, and 5.0 g / strand at the 345th strand. For the 2nd to 344th strands and the 346th to 688th strands, taper control was performed such that the yarn tension was increased by 0.009 g for each strand approaching both ends based on the 345th strand (the strand located in the center of the 689 strands). The yarn tension was controlled with the value rounded to the second decimal place. A total of 4 section beams were produced under the above conditions.

[0096] The obtained section beams were handled so as to be arranged in order, and a loom beam with a total of 2756 warp yarns was produced. Using the obtained loom beam, a glass cloth having a weaving density of 52.6 warp yarns / 25 mm and 52.6 weft yarns / 25 mm and a width of 1310 mm was woven on an air jet loom. At this time, 9.8 TEX glass yarn was used as the weft yarn, and the twist number of the glass yarn and the weaving conditions were adjusted so that the twist number of the weft yarn of the glass cloth became +0.50. The as - woven glass cloth was washed with ion - exchanged water, then dried, and heat - degreasing treatment was performed at 800 °C for 50 seconds.

[0097] Thereafter, a glass cloth (glass cloth with surface treatment) was obtained in the same manner as in Example 1.

[0098] 〈Example 6〉~〈Example 8〉 A glass cloth was obtained in the same manner as in Example 5, except that each value and each control were changed as described in the table.

[0099] 〈Comparative Example 1〉~〈Comparative Example 3〉 A glass cloth was obtained in the same manner as in Example 1, except that each value and each control were changed as described in the table.

[0100] <Method for Manufacturing Prepreg> 45 parts by mass of polyphenylene ether (manufactured by SABIC, Noryl SA9000), 10 parts by mass of triallyl isocyanurate, 45 parts by mass of toluene, and 0.6 parts by mass of 1,3 - di(tert - butylisopropylbenzene) were mixed in a stainless steel container and stirred at room temperature for 1 hour to prepare a varnish.

[0101] The glass cloths obtained in the examples and comparative examples were each rolled up. The glass cloth was drawn out from the obtained roll at a line speed of 2 m / min. At this time, the glass cloth was drawn out with a tension of 100 N applied thereto. While transporting the drawn - out glass cloth, it was immersed in the above - mentioned varnish, and then, by passing the glass cloth through a slit whose gap was adjusted so that the resin content became 68% by mass, the excess varnish was removed. Next, drying was performed under the conditions of a drying temperature of 130°C and a drying time of 1 minute and 30 seconds. Thereby, prepregs were obtained (examples and comparative examples).

[0102] <Amount of Meandering of Glass Cloth during Prepreg Manufacture> In accordance with the conditions during prepreg manufacture, the amount of meandering of the glass cloth was measured when the glass cloth was drawn out from the roll at a line speed of 2 m / min and with a tension of 100 N applied to the glass cloth.

[0103] Here, regarding the method for measuring the amount of meandering, the following conditions are considered. (1) A detector was placed at a distance of about 10 cm from the roll, and the glass cloth was drawn out along the MD direction so that one - side end of the glass cloth passed through the detector. (2) The glass cloth was drawn out over about 500 m, and during that time, at the detector, the amount of deviation in the width direction (TD direction) with respect to a predetermined reference value was detected. Here, the amount of deviation to the outside of the cloth was treated as a “+(plus) deviation amount”, and the amount of deviation to the inside of the cloth was treated as a “-(minus) deviation amount”, and each deviation amount was detected. (3) The sum of the maximum value of the detected "+ (plus) deviation amount" and the maximum value of the "-(minus) deviation amount" was calculated as the "amount of meandering".

[0104] 〈Yield of prepreg〉 From the obtained prepreg, a sample was obtained by cutting out a size of 400 mm × 400 mm. After sampling, a sample without wrinkles and fluff was regarded as a "good product" by visual inspection, and the number thereof was counted. Using the following formula: Yield of prepreg (%) = {(number of good product samples) / (number of samples)} × 100 the yield of the prepreg was determined based on this.

[0105] For the examples and comparative examples, their manufacturing conditions, evaluation results, etc. are shown in the following table. In the following table, looking at the relationship between the "amount of meandering" and the "yield", it was confirmed that the higher the "amount of meandering" of the glass cloth, the more the "yield" tended to decrease. It is presumed that the glass cloth with a larger "amount of meandering" is more likely to have wrinkles in the prepreg, and thus the "yield" is more likely to decrease.

[0106]

Table 1

Claims

1. A glass cloth having glass yarns as warp and weft yarns, wherein the twist number of the weft yarn is 0.40 to 1.80 turns / 25 mm or -1.80 to -0.40 turns / 25 mm, the absolute value difference in the twist number between the warp and weft yarns is 0.01 to 0.70 turns / 25 mm, the amount of warp crimp of the weft yarn is 35 mm or less, the silicon (Si) content in the glass yarn is 95.0 to 100% by mass in terms of silicon dioxide (SiO₂), a glass cloth.

2. The silicon (Si) content in the glass fiber is 99.0 to 100% by mass in terms of silicon dioxide (SiO 2 ), and the glass cloth according to claim 1.

3. The glass cloth according to claim 1 or 2, wherein the twist number of the warp yarn is 0.40 to 1.80 turns / 25 mm or -1.80 to -0.40 turns / 25 mm.

4. The glass cloth according to claim 1 or 2, wherein the glass yarn is treated with a surface treatment agent containing a silane coupling agent.

5. The surface treatment agent is represented by the following formula (1): X(R) 3-n SiY n ...(1) (In the formula, X is an organic functional group having at least one of an amino group and an unsaturated double bond group having radical reactivity, Y is each independently an alkoxy group, n is an integer of 1 or more and 3 or less, and R is each independently a group selected from the group consisting of functional groups composed of hydrocarbon groups having 1 to 10 carbon atoms.) The glass cloth according to claim 4, comprising the silane coupling agent represented by the formula.

6. The glass cloth according to claim 5, wherein X in the formula is an organic functional group that does not form a salt with an ionic compound.

7. The glass cloth according to claim 5, wherein X in the formula does not contain an amine or an ammonium cation.

8. The glass cloth according to claim 5, wherein X in the formula is an organic functional group having at least one of a methacryloxy group and an acryloxy group.

9. The glass cloth according to claim 5, wherein R in the formula is a group selected from the group consisting of a methyl group, an ethyl group, and a phenyl group.

10. The glass cloth according to claim 1 or 2, wherein the TEX of the warp and weft yarns is 0.5 to 40 g / 1000 m.

11. The glass cloth according to claim 1 or 2, wherein the bulk dielectric tangent of the glass constituting the glass yarn is in the range of 0.001 or less at 10 GHz.

12. The glass cloth according to claim 1 or 2, which is for a printed wiring board.

13. A prepreg containing the glass cloth according to claim 1 or 2, a thermosetting resin, and an inorganic filler.

14. A printed wiring board comprising the prepreg according to claim 13.

15. An integrated circuit comprising the printed wiring board according to claim 14.

16. An electronic device comprising the printed wiring board according to claim 14.

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